import os

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import plotly.express as px

Modify Data

Create Merged .csv File with Data from All Cities

# setup global variables - data file directory and name
DATA_FILES_DIR = 'data'
DATA_FILE_NAME = 'data.csv.gz'

all_data_files = os.listdir(DATA_FILES_DIR)

def create_data_file():
    # read each data original data file and concatanate it to single df
    os.chdir(DATA_FILES_DIR)
    df = pd.concat(map(pd.read_csv, all_data_files), ignore_index=True)
    os.chdir('..')   # return to previous dir - main dir
    
    # remove some patterns from city column    
    df['city'] = df['city'].str.replace(',Croatia', '')
    df['city'] = df['city'].str.replace(r'+', ' ')
    
    # sort data by datetime and city and save it to .csv file
    df = df.sort_values(by=['date_time', 'city'])
    df.to_csv(DATA_FILE_NAME, index=False, compression='gzip')
    print('Data processed successfully')

# create data file if does not exist
if not os.path.exists(DATA_FILE_NAME):
    print('Creating data file')
    create_data_file()
else:
    print('Data has already been processed')

Data has already been processed

Import Data & Data Info

# import data 
df_data = pd.read_csv(DATA_FILE_NAME, compression='gzip')
df_data.info()

<class 'pandas.core.frame.DataFrame'>
RangeIndex: 1081584 entries, 0 to 1081583
Data columns (total 37 columns):
 #   Column             Non-Null Count    Dtype  
---  ------             --------------    -----  
 0   date_time          1081584 non-null  object 
 1   sunrise            1081584 non-null  object 
 2   sunset             1081584 non-null  object 
 3   moonrise           1081584 non-null  object 
 4   moonset            1081584 non-null  object 
 5   moon_phase         1081584 non-null  object 
 6   moon_illumination  1081584 non-null  int64  
 7   time               1081584 non-null  int64  
 8   tempC              1081584 non-null  int64  
 9   tempF              1081584 non-null  int64  
 10  windspeedMiles     1081584 non-null  int64  
 11  windspeedKmph      1081584 non-null  int64  
 12  winddirDegree      1081584 non-null  int64  
 13  winddir16Point     1081584 non-null  object 
 14  weatherCode        1081584 non-null  int64  
 15  weatherIconUrl     1081584 non-null  object 
 16  weatherDesc        1081584 non-null  object 
 17  precipMM           1081584 non-null  float64
 18  precipInches       1081584 non-null  float64
 19  humidity           1081584 non-null  int64  
 20  visibility         1081584 non-null  int64  
 21  visibilityMiles    1081584 non-null  int64  
 22  pressure           1081584 non-null  int64  
 23  pressureInches     1081584 non-null  int64  
 24  cloudcover         1081584 non-null  int64  
 25  HeatIndexC         1081584 non-null  int64  
 26  HeatIndexF         1081584 non-null  int64  
 27  DewPointC          1081584 non-null  int64  
 28  DewPointF          1081584 non-null  int64  
 29  WindChillC         1081584 non-null  int64  
 30  WindChillF         1081584 non-null  int64  
 31  WindGustMiles      1081584 non-null  int64  
 32  WindGustKmph       1081584 non-null  int64  
 33  FeelsLikeC         1081584 non-null  int64  
 34  FeelsLikeF         1081584 non-null  int64  
 35  uvIndex            1081584 non-null  int64  
 36  city               1081584 non-null  object 
dtypes: float64(2), int64(25), object(10)
memory usage: 305.3+ MB

df_data.head(5)

	date_time	sunrise	sunset	moonrise	moonset	moon_phase	moon_illumination	time	tempC	tempF	...	DewPointC	DewPointF	WindChillC	WindChillF	WindGustMiles	WindGustKmph	FeelsLikeC	FeelsLikeF	uvIndex	city
0	2016-10-31 00:00:00	06:40 AM	04:50 PM	07:02 AM	05:38 PM	New Moon	0	0	5	40	...	2	36	1	34	16	25	1	34	3	Bakar
1	2016-10-31 00:00:00	06:42 AM	04:54 PM	07:05 AM	05:41 PM	New Moon	0	0	14	58	...	8	47	12	54	22	35	12	54	4	Bale
2	2016-10-31 00:00:00	06:38 AM	04:50 PM	07:00 AM	05:38 PM	New Moon	0	0	9	48	...	5	41	6	43	17	28	6	43	3	Banjol
3	2016-10-31 00:00:00	06:26 AM	04:44 PM	06:48 AM	05:31 PM	New Moon	0	0	14	57	...	5	41	12	53	20	33	12	53	4	Baska
4	2016-10-31 00:00:00	06:41 AM	04:52 PM	07:04 AM	05:39 PM	New Moon	0	0	5	40	...	2	36	1	34	16	25	1	34	3	Boljun

5 rows × 37 columns

Correlation

# global variables
CORRELATION_DIR = 'correlation_plots'

# recreate directory if does not exist
if not os.path.exists(CORRELATION_DIR):
    print(f'Creating folder {CORRELATION_DIR}')
    os.mkdir(CORRELATION_DIR)

# to always have the newest plot versions, delete file before creating new one
def remove_file_if_exists(file_path):
    if os.path.exists(file_path):
        os.remove(file_path)

# function to calculate correlation matrix values
def create_correlation_matrix(data, towns, field):
    towns_cnt = len(towns)
    # init zero matrix with m=n=count of cities 
    # set values to -13, just to be sure it is an imposible correlation value
    ret_matrix = np.zeros((towns_cnt, towns_cnt)) - 13 

    # iterate through every city combination and calculate the correlation
    # normalize the date for each town
    for i, town1 in enumerate(towns):
        town1_values = np.array(data.loc[data['city'] == town1][field])
        town1_values = (town1_values - np.mean(town1_values)) / (np.std(town1_values) * len(town1_values))
        # correlation 1 on diagonal
        ret_matrix[i,i] = 1.0
        
        # having in mind that ret_matrix[i,j] == ret_matrix[j,i]
        for j, town2 in enumerate(towns[i+1:], i+1):
            town2_values = np.array(data.loc[data['city'] == town2][field])
            town2_values = (town2_values - np.mean(town2_values)) / (np.std(town2_values))
            ret_matrix[i,j] = np.correlate(town1_values, town2_values)[0]
            ret_matrix[j,i] = ret_matrix[i,j]
    
    return ret_matrix

unique_towns = sorted(list(df_data['city'].unique()))

CORRELATION_COLUMN = 'tempC'  # choose which column will be used for analysis
CORRELATION_DATA_FILENAME = f'{CORRELATION_COLUMN}_correlation_data.npy'

# check if we already have correlation matrix saved
if os.path.exists(CORRELATION_DATA_FILENAME):
    print('Correlation file exists!')
    corr_matrix = np.load(CORRELATION_DATA_FILENAME)
else:
    print('Correlation file does not exist.. Creating one...')
    corr_matrix = create_correlation_matrix(data=df_data, towns=unique_towns, field=CORRELATION_COLUMN)
    np.save(CORRELATION_DATA_FILENAME, corr_matrix)

Correlation file exists!

# plot correlation matrix
CORRELATION_MATRIX_FILENAME = f'{CORRELATION_DIR}/{CORRELATION_COLUMN}_correlation_matrix.png'
remove_file_if_exists(CORRELATION_MATRIX_FILENAME)
fig = px.imshow(corr_matrix, x=unique_towns, y=unique_towns,
               width=1300, height=1300)
fig.update_layout(title_text='Correlation Matrix', title_x=0.5)
fig.write_image(CORRELATION_MATRIX_FILENAME)
fig.show()

# function to plot correlation bar chart
def plot_town_bar_chart(cor, towns, field):
    asix_range = np.arange(0, len(towns))
    for i, town in enumerate(towns):
        CORRELATION_IMAGE_FILENAME = f'{CORRELATION_DIR}/{field}_{town}_correlation_chart.png'
        remove_file_if_exists(CORRELATION_IMAGE_FILENAME)
        
        curr_towns = towns.copy()
        curr_towns.remove(town)
        
        curr_values = cor[i]
        curr_values = np.delete(curr_values, i)
        
        curr_df = pd.DataFrame({'CITY': curr_towns, 'VALUES': curr_values})
        fig = px.bar(curr_df, x='CITY', y='VALUES',
                    hover_name='CITY', width=1000, height=500)
        fig.update_layout(title_text=f'Correlation - {town}', title_x=0.5)
        fig.update_xaxes(tickangle=90, tickmode='linear', title='')
        fig.update_yaxes(title='%', range=[0.5,1.01])
        fig.write_image(CORRELATION_IMAGE_FILENAME)
        
        if town == 'Rijeka':
            fig.show()

# call function for creating bar charts for each town
plot_town_bar_chart(corr_matrix, unique_towns, CORRELATION_COLUMN)

Export to HTML

# save notebook before nbconvert
import IPython

%%javascript
IPython.notebook.save_notebook()

# export notebook results to HTML
!jupyter nbconvert --to=HTML correlation.ipynb